This paper describes the specific properties of an emulsion which was prepared with “soft hydrophilic nanoparticles” instead of an ordinary surfactant. Since the emulsion is stabilized by the hydrophilic nanoparticles which are thermodynamically irreversibly attached to the oil droplets' surface, the emulsion has been named the “three-phase emulsification method” to distinguish it from conventional emulsions. Three-phase emulsion is different from conventional emulsion in many ways. For example, not only the case of adding salt or acid, the emulsion may be diluted or concentrated is stable. Further, the particle size of the emulsion can be prepared anywhere from 100 nm; it can also be prepared from sizes that cause the Rayleigh scattering to show a structural color to a size of several tens of microns. Furthermore, since the three-phase emulsion has a structure which holds the hydrophilic nanoparticles onto the oil droplets, it can be seen that three-phase emulsion is hydrophilic in comparison with the conventional emulsion. Therefore, the three-phase emulsion called a “water retention emulsion”, showing that it is possible to produce an emulsion having high wettability when applied to cosmetics.

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Social impression management has become important today for women who have diverse roles in the social communities of work and home. Effective eye makeup products, especially a mascara that can create the most natural and beautiful eyelash curves, are critical for creating a positive impression. To produce eyelashes with a natural and aesthetic curve, a film former with hardness to resist internal stress of eyelashes and film strength to resist external deformation due to blinking is required. However, in conventional waterborne acrylic resin dispersions, which are commonly used to control eyelash shapes, the aggregation of the brittle acrylic crystals induces a significant decrease in the film strength. In this study, we focused on controlling the microstructure of a film by utilizing the acrylic-core-polyurethane-shell (ACUS) particles. Utilizing the optimized acrylic Tg, urethane monomer composition, and core/shell weight ratio, a rigid acrylic core was wrapped in a flexible polyurethane shell which coalesced to form an extremely uniform microstructured film with an extreme hardness and film strength. The ACUS film was shown to control the aesthetic eyelash curves with an accuracy of 0.1 increments of b-values evaluated using a logarithmic curved eyelash model with variable b-values. The developed mascara showed beautifully curved eyelashes that could dramatically enhance a women's social impression.

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In this research, we have explored the potential of pineapple fruit extract containing glucosylceramides (PFEG) for oral intake and external application, and found it has a number of efficacies for skin beautification. These days, plant-derived ceramide (glucosylceramide) has become commonplace in the skin care market. We have developed a pineapple fruit extract containing glucosylceramides (PFEG) from the edible part of pineapple. Ceramide is contained in the horny layer which is located at the outer layer of the skin. About 55% of intercellular lipids in the horny layer are composed of ceramides. Ceramide plays an important role in maintaining skin moisture and skin barrier function. It is reported that the ceramide content in the skin decreases as one ages, and people suffering from dry skin and atopic dermatitis have low ceramide content. We have already proven in other research that PFEG has beautifying efficacies such as moisturizing and skin lightening by oral intake. In this study, PFEG showed an up-regulating effect of mRNA expression related to moisturizing effects and ceramide synthesis in an in vitro study. The clinical study showed that PFEG improved skin dryness by sodium dodecyl sulfate (SDS) treatment by increasing ceramide content in the skin. PFEG inhibited the melanogenesis in melanocytes. Interestingly, it was suggested that PFEG strongly inhibited melanogenesis and pigmentation by a combination of oral intake and external application compared to only oral intake. These results indicate that PFEG exerts moisturizing effects by promoting ceramide synthesis and brightening effects simultaneously, and what is more, the beautifying efficacies of PFEG synergistically increase by oral intake and external application compared to either oral intake or external application.

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Natural/organic cosmetics are increasingly popular, but there is a lack of sunscreens with high SPF numbers in this market. One reason is the difficulty of emulsifying UV absorbers with high polarity. By applying a “liquid crystal emulsification method”, we succeeded in producing stable sunscreens with high UV protective effect. Small angle X-ray scattering measurement revealed that polyglycerol fatty acid esters, having a hydrophile-lipophile balance (HLB) between 6.0 and 12.0, formed a liquid crystal with the addition of water. We confirmed that a liquid crystal, composed of polyglycelyl-10 stearate, had the capacity to contain a large volume of UV absorbers. The mean particle size of the emulsion prepared by diluting a liquid crystal of polyglycelyl-10 stearate with UV absorber was 3.20 μm. It is known that polyols can change the HLB of surfactants, and the liquid crystals in polyglycelyl-10 stearate disappeared after the addition of 1,3-butandiol. Meanwhile, addition of glycerol expanded the area where liquid crystal can be formed. The mean particle size of the emulsion fell to 0.59 μm when glycerol was added, and the emulsion stability was significantly enhanced. Observation of a thin dry film of the prototype sunscreen cream containing 10 wt% of UV absorber by infrared micro-spectrometry showed uniform distribution of the UV absorber. The SPF of the prototype sunscreen was 50 (by ISO standards). This new emulsification technique will make it possible to formulate natural sunscreens with high UV protective effect, which will increase consumer satisfaction.

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Recently a number of studies on the facial skin pores have been reported. The shape of pores is ellipsoidal but non-circular, and the elliptic distortion increases with age. Many factors such as menstrual cycle, ultraviolet irradiation, sebum secretion, and dry skin affect the size of pores. However, few studies focus on the relationship between the direction of pores (the angle of the long axis of the ellipse) and the cutaneous mechanical-anisotropy. This study examined the pore size and its direction at six different sites on the face by image analysis with a video microscope and software (Integral, Tokyo, Japan). The directions of pores in the forehead, chin, and upper and lower cheeks of the both sides of the face run along the Langer's lines. The size of pores in the upper cheek was larger than those of other sites. This study also measured the cutaneous mechanical-anisotropy with CutiScan (C＋K, Cologne, Germany). The low extensible direction of the skin was found to correspond to those of the pores and the Langer's lines. Finally, this study investigated the effect of a 4-week treatment with skincare products on the shape of pores. The total area of pores significantly decreased with improvement in the skin condition, which was confirmed by an increase in water content in the stratum corneum and a decrease in the transepidermal water loss. However, the direction of pores could not be changed.

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Conspicuous facial pores are a skin problem. We focused on facial pores and developed software which can analyze the shape of pores. The images taken by video microscope have uneven brightness caused by inside light sources. First of all, we developed a processing method to obtain an image suited for analysis, by removing unevenness in brightness and noises such as hairs. Next, skin pores were extracted from the images obtained by the newly developed image analysis software. Subsequently the shape, the direction of major axis, and the area of each pore were calculated by an approximate ellipse drawing. Finally, we showed a scatter diagram to display the facial pore characteristics.

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Market volume of sensitive skin care products has continuously increased along with the increase in people's concern about sensitive skin due to more stressful lifestyles and environmental degradation. We investigated whether dipotassium glycyrrhizate (DPG), the active ingredient which is most frequently utilized in sensitive skin care products in Japan, is able to reduce the expression of nerve growth factor (NGF), which upregulates hyperesthesia in the skin, a characteristic condition of sensitive skin, with an in vitro study. Furthermore, suppression effects in some parameters of sensory discomfort were found in a human stinging test using a formulation containing 5% lactic acid and with/without 0.2% DPG. In this study, DPG suggested the possibility of improvement for persons with various kinds of sensitive skin.

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